Seiwert said the sirens had passed a weekly test. He said it is unclear what the problem was, but that city equipment vendors have been out to make needed repairs.

When the system failed, the Nickerson Fire Department implemented a backup plan, which includes firetrucks going through the streets and sounding the sirens to alert residents about the imminent tornado.

Seiwert said the tornado was on the ground for 22 minutes and moved northwest at about 10 mph. At least two homes were damaged. No injuries were reported.